If it is a high pitch sound, then the color wheel needs to be replaced. While this sounds cheap, the problem is that some InFocus projector color wheels came with the engine and was not sold separately. Engines cost $1000-$2000. The color wheel itself costs under $100.
If it is a more low pitch sound, then the fan could be going bad. This should only cost at most $10.
2005...that means your warranty just expired. InFocus projectors range between 1-2 warranties. You can spend a few hundred dollars to repair the unit or you can invest in another projector. The part itself is cheap, but typically it costs $100 for labor. The fan costs $5. The color wheel may cost around $50.
Go to http://www.infocus.com/support
and plug in your zip code to find the nearest service center. Parts are not sold to consumers, so you cannot repair it yourself.